The invention generally relates to potable water systems for aircraft, and more particularly pertains to a system configuration which allows unused water to be recovered for later use.
On commercial aircraft with in-flight catering services, it is common for one or more of the galleys installed on the aircraft to be “wet” i.e. to have a water supply (potable water), waste water drainage, and on occasion water used in a waste disposal unit (foul water—post use).
The potable water is supplied under pressure to the galley, while gravity, which can be assisted by a vacuum, is used in water drainage and waste disposal. Potable water is used as drinking water, beverage making and cooking, such as in steam ovens, rice boilers and the like, and has to be fit for human consumption, to this end it has to meet certain minimum health and safety standards and is generally filtered to improve taste, smell and to remove bacteria, according to specific airline policy. The plumbing system therefore encompasses all aspects of water usage on a galley, its associated hardware, components and galley equipment which either consume or facilitate water handling.
All galley plumbing systems must pass design and regulatory requirements specified by the aircraft manufacturers and have to undergo proving tests to ensure that the potable, waste and foul water systems are fully functional and remain separated ensuring cross contamination cannot occur.
Also, when the aircraft shuts down on completion of a flight, or for longer periods of storage or maintenance, all of the systems must be capable of draining completely within a specified time, no residual water, that could potentially become contaminated, is allowed to be retained within the plumbing system, to this end it must be capable of letting air to be displaced during filling, and air to enter the system during drainage allowing rapid water displacement.
It has previously been common practice for potable water that has passed through a water filter to be regarded as waste water, however recent changes in policy by aircraft manufacturers driven by the need to conserve water means that in some instances potable water only becomes waste water when potable water has entered a galley sink, has been exposed to air, or has become foul water such as passing through a galley waste disposal unit, for example, and all other water fed devices, including water boilers, faucets, ovens, filters and the like, can now be allowed drain back into the fresh water tanks.
A galley plumbing system is needed that is capable of effectively and efficiently recovering potable water from water fed devices upon aircraft shutdown and refilling such water fed devices in preparation for a resumption of service.